BMW M4 2015 MotoGP Safety Car tests new water injection system – to debut in an M car soon

BMW will once again provide the safety car for MotoGP, and like last season, the 2015 MotoGP Safety Car will be the RM750k BMW M4 Coupe. But unlike last year’s white M4 safety car, the black 2015 edition doesn’t just feature every item in the BMW M Performance Parts catalogue, we get a preview of some new tech as well.

The M Division has equipped the M4’s 431 hp inline-six with a water injection system. Water injection makes it possible to raise the upper performance limits, which have otherwise been restricted thermally.

Power and torque aside, the water injection system also improves efficiency with benefits in full-load consumption and exhaust emissions. Benefits at both ends of the scale, can’t argue with it!

The system makes use of the water’s physical effect during the vaporisation process to extract the energy required from the environmental medium. Water is injected into the intake module’s collector as a fine spray, significantly cooling the exhaust air during vaporisation. This lowers the discharge temperature in the combustion chamber and thus reduces the tendency for knocking, allowing the turbo engine to have higher charging pressure and an earlier ignition point.

Lower process temperatures also reduce the formation of hazardous substances, in particular nitrogen oxide (NOX). Water injection consequently “dramatically improves the effectiveness of the engine,” BMW says. Also, improved performance can be achieved without increasing the heat applied to performance-related components, meaning that reliability is not affected.

In this M4, BMW has opted for a layout with three injection valves in the plenum chamber, each supplying two cylinders. Located in the boot is a water tank with a gross volume of about five litres, which houses the water pump, sensors and valves, all controlled by the engine electronics.

In practice, the pump feeds the water to the injectors at a pressure of ten bar, whereby the appropriate volume is supplied depending on load, engine speed and temperature.

On track, the water tank has to be replenished whenever the car refuels. During more normal operation, the intervals between water refills are considerably longer, roughly once every five refuelling stops. To ensure the system is as suitable as possible for daily use, it does not require any additional maintenance, BMW says.

Not just a fun project for the engineers, water injection will be going into a production M car soon. Munich says that following extensive testing via the MotoGP series, the system “will also be employed in a BMW M production model in the near future.”

Danny Tan loves driving as much as he loves a certain herbal meat soup, and sweet engine music as much as drum beats. He has been in the auto industry since 2006, previously filling the pages of two motoring magazines before joining this website. Enjoys detailing the experience more than the technical details.

Hardly new technology. BMW used water injection it on their mid-80s F1 turbo engines to extract 1,450 bhp from a 1.5 litre turbo engine. Interesting that it took 30 years before it’s been considered for production.

You can either post as a guest or have an option to register. Among the advantages of registering is once a name has been registered, a guest cannot post using that name. If you have an account, please login before commenting. If you wish to have a profile photo next to your name, register at Gravatar using the same e-mail address you use to comment.